ST Chamaeleontis and BP Coronae Australis: Two Southern Dwarf Novae Confirmed as Z Cam Stars

Volume 42 number 1 (2014)

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Mike Simonsen
AAVSO, 49 Bay State Road, Cambridge, MA 02139; mikesimonsen@aavso.org
Terry Bohlsen
Mirranook Observatory, Booroolong Road, Armidale, NSW, Australia; terry.bohlsen@bigpond.com
Franz-Josef Hambsch
Oude Bleken 12, Mol, 2400, Belgium; hambsch@telenet.be
Rod Stubbings
2643 Warragul—Korumburra Road, Tetoora Road, Vic, Australia; stubbo@sympac.com.au

Abstract

Z Camelopardalis (Z Cam) stars are a subset of dwarf novae distinguished by the occurrence of "standstills" -- periods of relative constant brightness one to one and a half magnitudes fainter than maximum brightness. As part of an ongoing observing campaign, the Z CamPaign, the authors focused attention on several Z Cam suspects in the southern hemisphere. Two stars, BP CrA and ST Cha were found to exhibit standstill behavior in 2013, thus confirming them as Z Cam type systems. This adds two more bona fide members to the nineteen confirmed Z Cams, bringing the total to twenty-one.